JPH0279702A - Individual transportation tool control system - Google Patents

Abstract

PURPOSE: To provide a powered wheelchair which can be freely operated by providing a removable programmable memory containing a key code to enable only an authorized user to operate the wheelchair and constants for use in an algorithm prescribed for that particular user. CONSTITUTION: Operation of a command module is controlled by a microprocessor 32 using an RAM 34, a PROM 36 and an EEPROM 37. A key PRO 38 is connected with a bus 22. The key PRO 38 provides a code for enabling operation of a powered wheelchair, processes an input data and provides constants for use in an algorithm which operates a wheelchair in accordance with a prescription for that particular user's needs. The key PRO 38 also contains constants for modifying the control algorithm of wheelchair in the acceleration, deceleration, abrupt stop, maximum speed and operation mode regions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to control systems for powered wheelchairs or personal transport vehicles (PTVs), and more particularly to custom mechanisms for such wheelchairs.

BACKGROUND OF THE INVENTION Powered wheelchairs come in many different types depending on the abilities of the individual expected to use the wheelchair. Some wheelchairs have the ability to climb stairs and other features. A joystick is used as a typical input mechanism to control both the speed and direction of the wheelchair.

However, some wheelchair users are unable to operate the joystick due to their disability.

Other input mechanisms include a voice control device, a head mount that responds to head movement, and an air pressure sensor that responds to straw breath air. According to the format of the input used,
The input circuitry must be modified to process and respond to the human power signals to provide the appropriate drive signals to the wheelchair motors.

Furthermore, there are various differences between users regarding special manual forms such as joysticks.

For example, some users can barely operate a joystick because their hands constantly shake. Thus, special filter circuits can be included to counteract the effects of such tremors. Additionally, some users may only be able to make jerky movements, which will result in very rapid accelerations or decelerations unless corrective action is taken. Such modifications can be made by using different circuits or by providing the switch as a manual component to the processor behind the wheelchair that can be configured according to the needs of a particular user.

Obviously, the use of such a switch complicates the circuitry, requires a technician to adapt the wheelchair to a particular user, and increases cost.

For example, U.S. Pat. No. 4,634,941 discloses the use of variable resistors for acceleration and deceleration control in column 8.

Certain wheelchairs are used in environments with a large number of users, such as a health center, where the wheelchair must be refitted each time a new user is provided with the wheelchair. Furthermore,
Access to a wheelchair must be controlled where there is a risk that a particular user may be injured in a wheelchair that is not compatible with that particular disability.

[Means to solve the problem]

The present invention provides a removable programmable memory that contains both the key code and the constants used in the algorithm to drive according to the prescription required by this particular user so that only authorized users can drive. It is a powered personal vehicle (PTV) with Control signals from an input such as a joystick are modified by an algorithm according to a prescription for a particular user. This recipe is stored in the programmable memory and loaded into the computer when the memory is inserted. This key code in memory may allow various levels of access, such as access for one particular user, one particular group, surgeon access, and technician access.

In the preferred embodiment, electrically erasable programmable read only memory (EEPROM) is used as the memory key.

Two processors, i.e., operate the algorithm and P
A first control processor is used to control the TV motor, and a second command processor is used to control the display panel, receive input, and modify the input according to the prescription. The modifications made in the command processor are filtering of input signals and control of acceleration and deceleration.

The invention also uses a unique display with an icon in the shape of a wheelchair. The status of the PTV relative to its mode of operation is indicated by different elements of the icon that light up to indicate certain statuses. For example, a pair of downward-facing eyes may cause an ultrasound drop-off.
Indicates that the sensor is activated.

For a more complete understanding of the nature and advantages of the invention, reference should be made to the following detailed description in conjunction with the accompanying drawings.

〔Example〕

FIG. 1 shows a wheelchair lO using the invention.

One of the motor drive wheels I2 appears to be a tread 14 used for stair heights.

A joystick 16 is mounted on one arm of the chair along with a control panel 18 with a display and push buttons. The joystick and control panel can also be placed on separate arms.

According to FIG. 2, control signals from joystick 16 and control panel 18 are provided to command module 20. Referring to FIG. Signals from control panel 18 are provided on address and data bus 22. The signal from joystick 16 produced by the variable reluctance sensor is an analog signal provided on line 24 to analog-to-digital converter 26 of command module 20. A/D converter 26 is connected to bus 22 .

Control panel 18 has a display 28 and pushbuttons 30. This pushbutton is desirably large and easy to press, and the display 28 uses large text so that it can be more easily seen by the user.

Operation of the command module is controlled by a microprocessor 32 using random access memory (RAM) 34, programmable read only memory (PROM) 36, and EEPROM 37.
M418 is connected to bus 22. key PROM
38 provides the code that enables the operation of the powered wheelchair and provides constants for an algorithm to process input data and adapt the wheelchair according to a prescription for a particular user or group of users.

Joystick 16 may be replaced with other input devices, such as a straw that performs breathing motions that cause changes in air pressure to an air pressure sensor. These manpower are A
It will be processed in the same way via the /D converter 26. The key PROM 38 will indicate the type of input to be used and will provide the data needed by the microprocessor 32 to modify the appropriate input data for the input type accordingly.

The key PROM is set to the EEPR at the same time as the initialization of the wheelchair.
Contains the key password loaded to OM37. This password is then stored in the EEPROM 37 and only the specific key FROM 38 with this password can energize the wheelchair. When the key PROM is inserted, microprocessor 32 compares this password to the password stored in EEFROM 37.

Several different levels of key codes can be used, such as master (clinician and/or field service), group (clinical setting), and individual.

Preferably, the key PROM is electrically programmable so that changes can be easily made.

The physician can contact the manufacturer with a new prescription and a new key PROM can be programmed and delivered. The new key PROM has a code indicating that it has not yet been used. Once the contents of the new key PROM are loaded into EEFROM 37, the key FROM 38
The code at is changed to indicate a used key PROM. This key PROM can then only be used to power a particular wheelchair with the same key password stored on that particular wheelchair. Additionally, all of the contents from this key PROM are downloaded to the command module's EEPROM, which then provides a redundant backup.

The key PROM also contains the necessary constants to modify the control algorithm for the wheelchair in the areas of wheelchair acceleration, deceleration, pasticity rejection, maximum velocity (translational and rotational movements) and membrane actuation modes. Also included.

The command module 20 has one command to the control module 44.
Dual R3 connected to paired series links 42
422 interface.

Two trees of serial lines are provided for full duplex communication with asynchronous non-initial connection capability. Communication is via the R S 422 interface 46 at the control module 44.
and one address and data bus 4
given to 8.

Microprocessor 50, RAM 552 and RO
M54 is connected to bus 48. control module 4
4 provides controlled power to the various motors via a pulse width modulation (PWM) generator 56 connected to the drives 62,64. Power supply 58 provides power from a series of batteries 60 and controls the charging of these batteries. The output of the PWM generator 56 is coupled to a motor drive 62 for the wheels of the PTV and another drive for other motors or solenoids for controlling seat position, seat rearward tilt, stair height track elevation position, etc. 64.

The motor drive section 62 includes left and right wheel motors 66 and 68.
is connected to. Encoders 70 and 72 are connected to motor 6.
6. From 68, feedback is provided to the microprocessor 50 via the interface (see FIG. 4).

A number of transducers 74 and ultrasound transducers 76 are connected to an analog-to-digital converter 78 of control module 44 .

Additionally, a control module that provides a digital output that bypasses A/D converter 78 may be used.

These inputs are shown in more detail in FIG.
Can be multiplexed via a single A/D converter.

FIG. 3 shows the command module 20 of FIG. 2 in more detail. In addition to the elements shown in FIG. 2, a push button 30 is connected to the microprocessor bus 22 via a key interface 102 and a second interface 104.

A liquid crystal display (LCD) 28 is an LCD drive circuit 10
6. The drive circuit 106 further includes a bus 22
The microprocessor 32 is driven by the above signal. In addition, a backlight control circuit 108 controls the backlight on the LCD display 28 through an indicator light, a light emitting diode (LED) 110.

FIG. 4 shows the controller module in more detail. Ultrasonic transducer 78 connects to microprocessor bus 4 via sonar interface +12.
8 is connected.

Microprocessor 50 sends a signal to drive transducer 76 via interface 112 and then monitors the echo signal.

In addition to ultrasound transducers, both digital sensors 1!4 and analog sensors 116 are provided. Digital sensor signals are provided to microprocessor bus 48 via digital interface 118. Analog sensor signals are provided to microprocessor bus 48 via analog to digital converter 120. Additionally, a supervisory signal from power supply 122 of power module 58 is provided via A/D converter 120 .

The power module 58 includes a power supply 122 and a power control circuit 12.
4. Battery charging circuit 126, including various drive R128. The drive 128 is connected to various actuators and solenoids 130. Drive 128 is powered by microprocessor 50 via interface 132 .

Motor drive module 134 includes the motor, drive, and encoder elements shown in FIG. Additionally, signals from encoders 70.72 are provided to microprocessor bus 4B via encoder interface 136.

Appendix ■ shows one basic example of a dual algorithm for controlling a wheel motor with a left motor power supply, xLo, and a right motor power supply, XRO. These two algorithms are based on the component calculations and constant modified proportional-integral-derivative behavior (P
ID) algorithm. Three constants are key FR
Given by OM38. These are Kt, K, and 8. Furthermore, the key FROM provides other algorithms or other coefficients to this algorithm for controlling other features of the wheelchair via the drive 64. Note that the constants K, and , are given to the filter algorithm for the command module 20, which is described in more detail in Annex II.

This Annex II filter algorithm is implemented in the command module 20. Essentially, this provides an empty band near the center of the joystick and along the X and Y axes, allowing the user to move in a straight line without holding the joystick exactly upright, and also allows Despite gentle movement, 1
to be able to stand still in one position. Furthermore, this algorithm provides greater responsiveness at slower speeds and less responsiveness at faster speeds to give the user greater maneuverability at relatively slower speeds and prevent sharp turns at relatively higher speeds. . Finally, a sudden action filter operation is performed.

Key PROM 38 provides various constants for both the filter algorithm in command module 20 and the control algorithm in control module 44, as well as other inputs to enable certain functions or set certain limits.

Examples of these inputs are as follows.

1. The maximum angle the user is allowed to interact with (9-36''') 2. The maximum speed the user is allowed 3. Display 28 of the user's next appointment with the clinician
Caution instructions above 4. Ability to enter track mode to activate wheelchair treads 5, ability to enter stair height mode 6, ability to shut off audio input mode (severely disabled people would not want the audio to be inconveniently cut off) 7. Ability to set the tilt and height of the chair (some users should not be allowed to change this) 8. Ability to cut off the ultrasonic drop-off detector (this does not apply if the wheelchair is placed on a pan etc.) 9. The range (in distance and/or time) after which the chair automatically enters the second function level (all of which are programmable as well).

This functionality is provided so that when a user is expected to make certain progress within a certain period of time, it is not necessarily necessary to visit a clinician to obtain higher functionality.

FIG. 5 illustrates the unique display of the present invention, including a character display 80 and a wheelchair icon 82. FIG. Also, a low battery indicator light 84, a caution symbol 86, a bell indicator light 88, a fuel level indicator light 90 and a status indicator light 9
2 is also shown.

The wheelchair icon 82 has several elements that light up to indicate the status of various situations.

A basic wheelchair icon without illuminated status indicators is shown in FIG. The various elements shown in FIG. 5 are as follows. First, high speed mode is indicated by line 94. Activation of the ultrasonic sensor is indicated by the eye and downward line 96. Activation of the speech synthesizer is indicated by line 98. Line 100 indicates that the seat is high and line 102 indicates that the backrest is sloping backwards. line 1
04 indicates that the stair height track is energized. line! 05 indicates that the "gentle descent" that cushions downward movement on the stairs is down and in place. Such "gentle descent" is described in U.S. Patent No. 4,671.
, No. 369.

As will be understood by those skilled in the art, the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. For example, different control algorithms than those described herein may be used. Alternatively, the joystick 16 can be replaced with a straw-type respiratory pressure sensor.

Accordingly, the disclosure of the preferred embodiments of the invention is intended to be illustrative of the scope of the invention as set forth in the appended claims, and not to be limiting.

(Appendix 1) PT ■, 1 Algorithm - Defined as below. That is, N= total number of the previous term. 4 range (0, 9) JTJ = joystick movement value in period j, where j = o
, -N, tolerance range (-128,127) JRJ" period j
The rotation value of the joystick at , where j=O, -
N. Tolerance range (-128, 127) CLJ = left motor encoder count during period j, where..., j =
0. -N. Tolerance range (-255° CRj = right motor encoder count during period j, where j = o,
-N, Tolerance range (-255°Kt = Joystick movement conversion constant. Tolerance range (0, 1, 5), = Joystick rotation conversion constant. Tolerance range (0,
0,5) K, = PWM conversion constant. Tolerance range (0, 1, 5) K =
Proportional error coefficient. 1 = derivative error coefficient in the tolerance range (-3,3)ρ. Tolerance range (-10,10)K,
= motor/motor error coefficient. Tolerance range (-10°1o)
,-,=previous right motor power (-255,255) Therefore, TJ =KtJTJ,j:0. -N Joystick corrected movement value RJ=, J,,,j =O,-N Joystick corrected rotation value E Lj" TJ Rj -Ct, J, j= 0+
-N Observation error of left motor Eゎ = T'' -R-J-CRJ, J = 0. −N Observation error P of right motor, = KpELo Proportional correction PR of left motor =
KpER8 Right side motor proportional correction I 1. = K I
sum (E,, j + J = 0, -N) Integral correction of the left motor IR2 to l5un + (ERj, j = O, -N) Integral correction of the right motor DL = to d (CLo - CL, -1) Left side Differential correction of motor DR=d (CRo-CR-1) Differential correction of right motor M,, second, (ERo-El,.) Left motor/motor correction MfI=-(ELo-ER,) Right side Motor/motor correction XLO= XL-1+ Km (P L+ r L+
DL 10ML) New left motor power XRO=XR-+ +x, (pR+I R+DR
+MR) New right motor powers xLo and xRo are next (-255,4255)L'
Limited i.

(Appendix TI) Joystick Filter Algorithm (Scope) This appendix describes the algorithm used to filter the joystick readings read from the analog-to-digital converter in the command module. This filtered reading is sent to the control module for configuration.

(Algorithm) Note: The positive X direction is the direction straight ahead of the joystick.

The positive X direction is the leftmost direction of the joystick.

1. Addition symbol The value (Xa+jYa) read from the A/D converter converts an unsigned number (0 to 255) into a signed number (-12
8 to +127), the value (x3
+jYs). Negative numbers are always represented in two's complement form. This conversion is performed by complementing the most significant digit (MSB) of the number.

2. The additive hysteresis value (xg+jY1) is calculated using the method below (Xsh+
jYsh). That is, if the MSB of the signed number is 1, set the carry by 1, otherwise reset it. Shift this number one place to the right by carrying.

This adds a negligible amount of hysteresis, increasing the number range from (-128 to +127) to (-64 to +6
Convert to 3).

3. Filter operation for the tremor component The value after the above processing (Xsh + j Ysh) is then:
It must be sieved by a real-time digital low-pass filter of order n. The filtration frequency of this filter (approximately 1.5 to +
5) 1z) is stored in the key PROM as a parameter. This type of filter corresponds to patients with involuntary tremor disorders.

The values Xsh and Ysh must be screened individually, which should remove the ac acid component of the quiver in both the translational and rotational scalers to yield the desired results.

The resulting values of X and Y are called (Xf+jYf).

4. Non-linear mapping for finer slow speed control and free bandwidth Now the value (Xf+jYf) is mapped by a table or another algorithm to yield the value (Xfm+jYfm), which does the following: That is, a, the small tilt of the joystick is the value (Xfm+j Yf
m), thereby increasing the resolution of the system in the region close to the neutral position of the joystick.

A large tilt of the joystick is determined by the value (Xfm+j
This also results in a relatively large deviation in Yfm), thereby reducing the resolution of the system in the range far from the neutral position of the joystick.

This type of mapping allows the user to have more control over the speed of the wheelchair, for example when the user moves very slowly in an office where precise positioning is required.

A typical mapping method can be obtained from the following equation. That is, X f m = R f m * cos (θ - f m)
Yfm=Rfm*5in(θ-fm) However, Rfm=89-45*log(89-Rf)θ
fm=θ f However, Rf'= (Xf*Xf+Yf*Yf)θ-f= a
One way to accomplish this in software without calculating the rctan (Yf/Xf) logarithm is to use a lookup table, but this requires a large amount of memory. A preferred method would be to use a relatively small resolution in the joystick and then use a look-up table, which would result in an even smaller look-up table.

Yet another method is to perform a division of the X and Y values. The larger of these two values is divided by the smaller one, and if the quotient is greater than a certain amount, mapping of X and Y is performed individually using a linear logarithm table.

A further method is to use a table with swapping and sign changes in the values of X and Y in only one quadrant, or even in only one half quadrant.

b. For the above table or algorithm, it is necessary to add a circular free band around the neutral position of the joystick. Also, a small circular full speed band would help achieve uniform response between chairs.

The linear front band is automatically generated by the mapping technique in the a term.

5. @ Scaling for large speeds (translational motion and rotary motion) The high speed mode and low speed mode are detected by the control module and the appropriate speed is sent by the command module
Please note that it is calculated from the values of and Y. This method would allow for greater accuracy in "low" speed modes by operationally treating the speed mode digit as another digit of joystick resolution.

For this, for example, the value (X,
Y) = (+[i3,0) will drive the chair at approximately 4.8 km/h (3 mph) if it is in the "low speed" mode and if it is in the "high speed" mode in the forward direction. means that you are trying to drive at about 9.7 km/h (6 mph).

Scaling to the maximum speed allowed can be done in either the command module or the control module.

6. Control of the maximum acceleration (translational and rotational movements) The maximum acceleration is automatically limited primarily by the position of the pillars of the system, or in other words by the slowness of their movement.

The formula below will limit the rate of change of X and Y individually. That is, if abs (Y(ni) -y(K-1))>Aym
Then, Yfmd=Y(ni-1)±Aym (The sign of Aym is the same as the sign of (Y(ni)-Y(ni-1))) Otherwise, Yfmd=Y(K) Also in the case of X, The same procedure is performed using Axm to generate Xfmd.

At higher speeds of movement, the value of Aym needs to be smaller, while at lower speeds this value can be larger. Therefore, the following steps are also added to improve only the value of Y. That is, Yfmd=
Yfmd*Ktr / Movement speed at that time 7, Slowing down the backward speed The backward speed must be much slower than the forward speed, this is because if X is found to be negative, then from the above process This is done by multiplying the resulting X and Y values by a constant. This constant is also stored in the key FROM.

Therefore, if X is negative, then Xcur + j Ycur = k reV* (
Xfffld + j Yfmd) else Xcur + j Ycur = 1 * (Xfm
d+j Yfmd) where k reV is the factor coefficient of the backward speed stored in the key PROM. Typically, k re
The value of V can be between 0.1 and 0.25. Therefore, the value (Xcur +j Ycur) is the value sent to the control module.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a powered PTV using the present invention;
Fig. 2 is a block diagram showing the control electrox of the present invention, Fig. 3 is a block diagram of the command module shown in Fig. 2,
4 is a block diagram of the control module of FIG. 2; FIG. 5 is a diagram of the visual display of the wheelchair of FIG. 1; and FIG.
The figure shows a basic wheelchair icon without an illuminated status indicator light. 10-...Wheelchair, 12-...Motor driven wheels, 14...
·tread,! 6- Joystick, 18...
- Control panel, 20... Command module, 22...
Address/data bus, 24... line, 26...
Analog/digital converter, 28...Liquid crystal display (LCD), 30-...Push button, 32...
...Microprocessor, 34...Random Access Memory (RAM), 36...Programmable Read Only Memory (PROM), 37...EEPRO
M, 38...Key PROM, 42...Serial link,
44--control module, 46-RS 422 interface, 48--address/data bus, 50
...Microprocessor, 52...-RAM, 54.
-ROM, 56--Pulse width modulation (PWM) generator, 58--Power source, 60--Battery, 62--
・Motor drive unit, 64...Motor drive unit, 66.68
...Wheel motor, 70.72...Encoder, 74
...Transducer, 76--Ultrasonic transducer, 78--Analog/digital converter, 80--Character display, 82--Icon,
84--Low battery indicator light, 86--Caution symbol,
88...Bell indicator light, 90...Fuel level indicator light,
92--Status indicator light, 94.96.98.100,
105--Line, 102--Key interface, +04--Second interface, 106-L
CD drive circuit, +08-... Backlight control circuit, 110-...
- Light emitting diode (LED), 112... Sonar interface, 114-... Digital sensor, 1
16-- Analog sensor, 118- Digital interface, 120- Analog/digital converter, 122- Power supply, 124- Power control circuit, +26 Battery charging circuit, 128-・
- Drive unit, 130... Solenoid, 132-... Interface, 134-... Motor drive module, 1
36...Encoder interface. 4 people) Engraving of drawings (no change in content) FIG#5゜Procedural amendments) October 2, 1989 Patent Application No. 148220, 1999 2, Title of Invention Personal Transport Vehicle Control System 3, Amendment Relationship with the case of the person who filed the patent application Patent applicant address: Natco Corporation 4, agent address: Shin-Otemachi Building 206-5, 2-2-1 Otemachi, Chiyoda-ku, Tokyo Date of amendment order: September 1999 26th of May (Shipping) 6. Application stating the representative name of the applicant subject to amendment

Claims (1)

Claims: 1. A personal transport device having wheels and a motor driving the wheels, comprising: a user control input for generating a drive signal; a control means for driving said motor in accordance with said drive signal modified by an algorithm; and a removable programmable memory for providing said key code to said control means, said vehicle being configured by said memory to be unique to a particular user. a memory providing constants for said algorithm so that it can be adapted to said algorithm. 2. The control means includes: a first command controller that filters and modifies the acceleration of the drive signal to produce a modified drive signal; and applying the algorithm to the modified drive signal to drive the motor. and a second controller for generating a power signal to generate a power signal. 3. The programmable memory is an electrically erasable programmable read-only memory (EEPROM).
The transportation device according to claim 1, characterized in that: 4. The control means includes an electrically erasable programmable read only memory (EEPROM) for storing the key code from the programmable memory, the control means storing the key code of the EEPROM from the removable memory. 2. The vehicle of claim 1, wherein the vehicle is programmed to compare with a key code provided by a programmable memory. 5. a plurality of sensors; an analog-to-digital converter connected to the sensor; a microprocessor connected to the analog-to-digital converter; and a microprocessor connected to the microprocessor and responsive to data or feedback from the sensor. and a drive circuit for driving one or more motors of the vehicle under control of the microprocessor.
Transportation equipment as described. 6. The vehicle of claim 1, further comprising a display having an icon in the shape of a wheelchair, wherein elements of the icon are displayed only when the portion of the vehicle represented by such an element is energized. transportation equipment. 7. In a personal transport device having wheels and a motor driving the wheels, a user control input for generating a drive signal, and responsive to a key code enabling actuation of the vehicle and filtering acceleration of the drive signal. and a first command controller that modifies and generates a modified drive signal, the first command controller including a programmable read only memory (PROM) storing the key code and executing a predetermined algorithm. a second controller for providing a power signal to the modified drive signal to drive the motor; and a removable programmable memory for providing the key code to the controller, and a removable programmable memory for providing the key code to the controller; a removable programmable memory providing constants for said algorithm so that the memory can be adapted to a particular user. 8. The PROM is electrically erasable (EEPR
8. The vehicle according to claim 7, characterized in that: OM).